GB594066A - Improvements in cut-off valves - Google Patents

Abstract

594,066. Fluid-actuated valves. WATERMAN, W. Aug. 27, 1943, No. 14026. [A Specification was laid open to inspection under Sect. 91 of the Acts, Feb. 1, . 1944.] [Class 135] A valve which is moved to the closed position by fluid flowing through the valve casing is normally kept in the open position by a holding means releasable by a predetermined fluid force acting on the valve member, the latter being also provided-with means operated by a reverse flow of fluid to guide it into re-engagement with the holding means. In the form shown in Figs. 2 and 3, the valve 10 mounted on a stem 17 is held away from its seat 11 during normal flow by a locking means comprising flanges 23 engaging the ends of splines 21 on the stem. Abnormal flow acting on vanes 13 turns the valve against the resistance of a flat torsion spring .15 so that the flanges 23 register with the spaces between the splines 21 and the valve is then moved by the flow into the closed position, a non-rotatable block 18 on the torsion spring sliding in a slot in the stem. Reverse flow will cause the flanges 23 to slide up the spaces between the splines and, at the end of the travel of the valve, spring 15 will rotate it into the position where the flanges 23 are engaged against the tops of the splines. In order to prevent operation by a surge, the valve is prevented from turning on its stem for a predetermined time, such turning being permitted only when a projection 54 on the valve can slip past a projection 55 non-rotatably mounted on an anchor 35. To effect the required delay, the valve stem is slidably mounted in the anchor and its rate of forward movement is controlled by a dashpot 57, the latter comprising a cylinder 38 formed by the anchor and a piston 40, carried by the stem. Fluid escapes from the dashpot between the cylinder and piston and also around the stem, and when the piston is returned to normal position by a light spring 47, fluid can enter the cylinder through an aperture 50 past a check valve 52. Specification 591,805 is referred to. The Specification as open to inspection under Sect. 91 comprises also valves closing after a predetermined volume of flow. In one form, Fig. 5 (Cancelled), the valve 65 carries actuating vanes 100 and a dashpot 69, similar to that shown in Figs. 2 and 3, but provided with a passage 67 which, when it slides clear of the dashpot cylinder, eliminates the action of the dashpot and allows the valve to close quickly. The valve can be made to respond to different volumes by means of an adjustable collar which varies the area of the passages past the vanes 100. In a modification, Fig. 6 (Cancelled), the dashpot cylinder is constituted by a bellows 85 of which the natural resiliency acts as a restoring spring to the valve. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specification 107,434, [Class 135].